Until revolution erupted in Aleppo in 2011, Syria’s second city had been home to a musical tradition venerated for eight centuries throughout North Africa and the Levant. This music is not much heard there now – most of the players and singers have fled – any more than the world’s most sophisticated artistry on the oud (the Middle Eastern lute) is much to be heard in its natural habitat, Baghdad.

Just two examples, from many around the world, of classical music under threat. Classical music? Yes. The phrase should not be seen as implying superiority to folk music, because all classical music has folk roots. But it does imply elitism, as classical music will typically evolve in a stable society where a wealthy class of connoisseurs has sponsored its creation by professionals. It will have had the time and space to develop rules of composition and performance, and to allow the evolution of a canon of works, or forms. Thus permitted within “classical” are musics which many people would automatically exclude: North American jazz, for example, and the Mande music of Mali and Gambia, because the template fits these traditions like a glove. The Andalusian music that originated in Moorish Spain and spread to Syria in the 12th century has a perfect claim to be called “classical”, as does Iraqi magic on the oud. To listen to the improvisations recorded by the oud’s supreme master Munir Bashir (1930-1997) is to be put in mind of Yo-Yo Ma playing Bach’s unaccompanied cello suites: both imply compellingly beautiful polyphonies through a single melodic line, and in both the silences are as eloquent as the sound.

Claiming ancestry going back to the 14-century empire of King Sunjata, Mali’s griot musicians meld poetry, history, folklore, and politics in song-forms based on a variety of different tunings: all that can be a lifetime’s study. Musicologists seeking to demonstrate jazz’s debt to African music have drawn up a long list of shared elements including the chorus cycle, call-and-response, bent or “blue” notes, and rhythmic and timbral contrasts, but jazz should be considered as the home-grown classical music of the US, not least because of the closeness with which its history mirrors that of European music, even if telescoped into a shorter time. It too was raised by a series of master-musicians to the level of an art-music, it too has evolved via a “classical” period through a series of modernist phases, and it too has its early-music revivalists (trad bands, Wynton Marsalis). Moreover – again like European music – it is currently unsure where to go next.

So how many classical traditions might there be? By my reckoning, at least 15, and though they seem diverse, they coalesce into a handful of stylistic families. Gong-chime music links Thailand, Laos, and Cambodia with Indonesia, while the music of China’s Tang dynasty was imported by Japan as its court music, a function which it still performs today. Meanwhile it’s a vertiginous thought that European classical music and the music of the Muslim Middle East should have a common root in classical Greek theory, which itself derived from ancient Babylon. Translated by Arab theorists in the eighth and ninth centuries, the writings of the Pythagoreans became the underpinning for the Arabic “science of music” which laid down rules for the structure of scales and the mathematical tuning of intervals; versions of this were then absorbed by the medieval church.

An even more arresting congruence is to be found along a line stretching eastwards from Morocco via Algeria, Egypt, Turkey, Iraq, Azerbaijan and Iran, to Uzbekistan, Tajikistan and Xinjiang. Classical music in all these states is based on the modal principle.

A mode differs from a scale in that it implies a specific melodic pattern in which some notes have more importance, more pulling-power, than others. In Middle Eastern modal music, known generically as maqam, each mode has its own sound-world, mood and set of social connotations. Maqam is in fact a quasi-philosophy, and it embraces a multitude of styles ranging from austere lute-accompanied Tajik maqom songs to the convivial maqam of a Syrian takht ensemble; from Azerbaijan’s barnstorming religious mugam to the chaste grandeur of Iraqi oud suites. And although Muslims strenuously deny that the azan – the intricate and melodically beautiful Islamic call to prayer – is “music”, that is yet another manifestation of maqam.

The scales used in maqam may differ from one country to another, but they all depend on microtonal refinement; while western music conventionally divides a whole-step interval into two semitones, Turkish makam can divide it into as many as nine infinitesimally fine pitch-differences. There is nothing “natural” about our doh-re-mi scale: “natural” simply means what the ear is used to.

There is no denying that European music is by far the most complex and many-faceted tradition the world has ever seen, thanks to its harmony-based polyphony, and to its notation, which has enabled composers to create their towering musical edifices. But Europe has no monopoly on sophistication: the improvisation on which almost all the other traditions are based allows sophistication of a different sort.

But what unites all classical musics (except jazz) is their religious dimension. The image of music coming down from the gods, and being sent back up to them – with professional performers as bearers of the sacred flame – is to be found in every civilisation. As is the idea of religious fulfilment implicit in the Zen Buddhist injunction “in one sound, become the Buddha”, and in the Sufi yearning for divine union, as expressed in Rumi’s lovely image of severance from the primal reed-bed: “Listen to the reed flute, how it does complain / And how it tells of separation’s pain.”

The Chinese guqin zither is traditionally believed to “sound the cosmos”; the ancient Greeks, for whom music was the dominant metaphysical principle of the universe, claimed to hear the music of the spheres. Even the contentious Islamic notion of music being haram, forbidden, is a back-handed testimony to the power that music possesses in the moral realm. Plato, who wanted to proscribe all music which was either sorrowful or associated with indolence and alcohol, would have understood that prohibition, as would those Christian sects throughout the ages which have forbidden the playing of instruments in church. With classical music, we enter the spirit world.

Yet a music can die, as a language can. Its death may be a natural consequence of evolutionary change, but it may also reflect the abrupt fall of an empire, or result from persecution: the Taliban lost no time in driving Afghanistan’s entire classical-music community into exile; Malian musicians are currently in the firing line for local Islamists.

A bigger threat comes via insidious erosion by the homogenising tide of western music, both commercial and classical. At the start of the last century, musicians across a swath of the globe stretching from Egypt to Japan were led by their rulers to believe that their indigenous monophonic styles were “backward” (only India was immune from this pernicious notion), and that, in order to compete on the international stage, they needed to deploy western polyphony. Microtonal scales, with their infinite variety, were ironed out in favour of European diatonic scales, and intimate solo instruments such as the Kazakh dombra lute found themselves grotesquely multiplied in the Soviets’ “folk” orchestras.

Today, armies of conservationists are rushing to the rescue. Unesco has designated a long list of musics as “intangible cultural heritage”; the Aga Khan Trust for Culture has set up a network of schools throughout central Asia where master-musicians now pass on their skills to young performers. Cylinder and shellac recordings are being studied by Middle Eastern musicians seeking to revive forgotten styles; governments are realising the value of traditional music as a propaganda tool.

But no music can survive long on artificial life-support: without a driving social impulse, it’s just a piece of museum culture, and this could well be the fate of the Uzbek-Tajik shashmaqom – a fusion of vocal and instrumental music, melodies, rhythms and poetry – whose continued existence now depends, despite its venerable history, on the enthusiasm of a handful of musicologists.

All of which raises a big question: if some classical musics go to the wall, will they be replaced by new ones? Not necessarily. Indeed, given the social conditions required for their gestation, and given the exponential rate at which the geopolitical order is now mutating, it’s hard to imagine new classical forms emerging anywhere in the foreseeable future.

Folk musics will continue to burst forth as they always have done. But with classical music, what we have may be all we’ll get, so we should treasure it.

The Other Classical Musics: Fifteen Great Traditions, edited by Michael Church, is published by Boydell and Brewer at £25.